Tool for explosively crimping electrical connectors



April 25, 1961 w. F. BROSKE ETAL TOOL FOR EXPLOSIVELY CRIMPING ELECTRICAL CONNECTORS 3 Sheets-Sheet 1 Filed April 17, 1958 we as ,3 m C) Q u G p 0 wflham F. BYLJHham E.

INVENTOR.

B roske J aqc x MJ-p April 25, 1961 w. F. BROSKE ETAL 2, 81,136

TOOL FOR EXPLOSIVELY CRIMPING ELECTRICAL CONNECTORS Filed April 17, 1958 3 Sheets-Sheet 2 INVENTOR.

(Qflham F. BrosKe. Qflham E Ja cox aJILM+W April 25, 1961 w. F. BROSKE ETAI. 2,981,130

TOOL FOR EXPLOSIVELY CRIMPING ELECTRICAL CONNECTORS Filed April 17, 1958 5 Sheets-Sheet 3 INVENTOR. (.Jflham F. Broske ywnham E.Ja coy ductor.

TOOL FOR EXPLOSIVELY CRIMPING ELECTRICAL CONNECTORS William F. Broske, Camp Hill, Pa., and William E. Jaycox, Bel Air, Md., assignors to AMP Incorporated, Harrisburg, Pa.

Filed Apr. 17, 1958, Ser. No. 729,103

9 Claims. (CI. 81-15) This invention relates to crimping electrical connectors onto conductors. More particularly it relates to effecting such crimps by means of explosive gases.

Prior art devices employ explosives to drive a piston whereby the piston cold forges the connector to the con- However the piston operates as a projectile which has a serious disadvantage from the standpoint of safety. If the device rnisfires or is fired without a connector therein, the potential danger is considerable.

It is an object of this invention to provide an explosively operated crimping tool wherein the explosive force operates directly upon the connector.

It is also an object of this invention to provide such a crimping tool wherein the connector is partially deformed after the tool is closed.

It is a further object of this invention to provide such a tool wherein the explosive can not be fixed until the tool is closed.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

Figure 1 is a plan View of a tool embodying the principles of this invention;

Figure 2 is an end view similar to the tool shown in Figure 1;

Figure 3 is a perspective view of the tool of Figure 1, shown in an open position;

Figures 4-7 are sectional views of the tool. shown in Figures 1-3; illustrating various phases of the closing and crimping operation;

Figure 8 is a fragmentary view of the firing mechanism employed in thetool illustrated above.

The preferred embodiment, as shown in Figure 1, is comprised of a body member 10, with a pair of handles 12 and 14 secured thereto. The body member may be made in two sections including a base 16 and a top 18, secured together'byhinge 20; The handle 12 is shown as fixed to base 16, whereas handle 14 is pivoted to top 18 by means of links 22.

As shown in Figure 3, the sections 16 and 18 of the tool include inserts 24 and 26 respectively. The insert 2 4 is arcuate and accommodates the ferrule portion of the connector C. Part of the insert may be relieved, as at 28, to accommodate a tongue portion of the connector. Recessed portions 30, and 30', as well as a bore hole 32 are provided for reasons which will be explained later. Theinsert 26 includes a recessed section which seats a member 36 containing an explosive charge.

The explosive charge container 36 is shown in the forni of a half-round tubular member having the explosive charge therein. One end may contain a primer cap 38, while the opposite end is sealed as at 40. The member 36 seats in the recess 34 with its ends disposed in the recesses 36', 30". The radius of curvature of the member 36 generally follows the radius of the connector. When the connector is positioned in the insert 24, it is partially surrounded by the U-shaped member 36. The insert 26, complements the insert 24 to seal the ferrule portion of the connector and the container 36 in a gastight chamber.

A conductor W may be inserted into the ferrule to be deformed therein. The ferrules are adapted to accommodate any one of a polarity of conductors over a range of sizes. Thus the smaller sized conductors will not occupy the entire volume of the ferrule. The crimping operation may be considered in two stages. In the initial stage the ferrule will be deformed until it snugly engages the conductor therein, i.e. the slack between the ferrule and the conductor is taken-up. This is an operation requiring a relatively low thrust to bend the metal.

ter the conductor and ferrule are in engagement, a relatively high thrust is requiredto compact the metal of the ferrule and the metal of the conductor into a secure gripping relationship. The thrust required continues to increase during the crimping cycle, since the more the metal is compacted, the more it resists further compaction. The final increment of crimping requires an extremely high crimping force when compared with the initial increment of crimping.

In order not to waste the crimping pressure of the explosive gases during the initial ferrule deforming (low thrust) stage, the illustrated embodiment provides a pie-crimping mechanical means for partially deforming the ferrule prior to making the final crimp. This saves the high pressure explosive force to accomplish the maximum of useful work. However in some instances pre-crimping may not be necessary, ,e.g. where original ferrule has the same inside diameter as the conductor.

As shown in Figure 4, a die 42 is slidable in the opening 32. The die is actuated by a cam 44, urged laterally by pin 46 in a passageway 48. Driving the pin and cam inwardly by closing the handle 14 operates the die 42 to partially deform the ferrule, note Figure 5. This deformation also secures the connector and conductor in position so that they are held tightly in the tool during the explosive cycle.

A mechanism for firing the explosive charge comprises a rod 50 disposed in the fixed handle 12 and slidably urged toward the body member 10 under influence of a spring 52. A detcnt 54 is movable ina bayonet slot 56, to permit the firing mechanism to be cooked and released.

The head of the firing mechanism includes a piston 58 slidable in a chamber 64). A firing pin 62 operated by the piston 53 rides in the aperture 30' and is adapted to excite the primer cap 38 thus exploding the charge.

The safety device comprises a pair of slidable tumblers 63 and 64 disposed in the piston 58. A laterally disposed piston 66 in chamber 68 is urged toward the firing piston 58. When the firing 'pin is in its forward position (Figure 4-), the safety piston 66 partially displaces the tumbler 63 to lock the firing mechanism while loading the tool.

Closure of handle 14 (Figure 5) in addition to precrimping the connector (described above), releases the firing mechanism by urging tumbler 63 into the firing mechanism and expelling piston 66 from the path of the 3 firing mechanism (note Figure 5) so that the firing mechanism is free to slide in the chamber 60. A clip 61 releasably retains the handles in the closed position.

The other tumbler 64 locks the firing mechanism against longitudinal movement if the tool is opened when the firing mechanism is cocked. As shown in Figure 6, movement of the handle 14 outwardly will release the tumbler 64 and again permit the piston 66 to lock the firing mechanism.

The firing pin 62 is mounted on a shoulder 70 which is slidable in a reduced section of the chamber 60. Its travel is restricted by sleeve 72 whereby the shoulder 70 forms a gas check to prevent escape of gases generated by the explosive charge.

In operation a connector C .(Figure 3) is inserted into the tool and the explosive charge container 36 positioned in the openings 30, and 30 so that it partially surrounds the connector. The conductor W is disposed centrally of the connector. The tool is then closed and a pin P" locks the tool in the closed position.

As shown in Figures 4 and 5, the handle 14, drives the pin 48 and the cam 44 to actuate the crimping die 42, thus partially deforming the connector and conductor. The cam 44 also moves the tumbler 63 to unlock the longitudinal movement of the firing mechanism. The rod 50 is retracted against the action of spring 52 until the detent 54 is positioned in the lateral section of slot 56. When it is desired to actuate the charge, the detent 54 is moved back into the longitudinal section of the slot 56 and the spring 52 drives the rod 50 with sufficient force to cause firing pin 62 to detonate the primer cap 38, thus exploding the charge.

It is noted that when the tool is cocked (Figure 6) it can not'be opened without locking it against finng. If the tool were opened (Figure 6), the spring 68 would drive piston 66 to dislodge tumbler 64, thus locking the firing mechanism against longitudinal movement. The spring clip 61 holds the tool closed, so that the handle 14 will not inadvertently open thus locking the firing mechanism.

As shown in Figures 6 and 7 the exploded charge causes the container to swell, and increases its inside diameter (note Figure 7). Since the tool prohibits outward expansion the volume occupied by the connector and conductor is decreased. Thus they are effectively crimped together to form a good electrical joint. The tool may then be opened and the connector and conductor removed.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made Without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

We claim:

1. A hand tool for crimping electrical connectors comprising a body member, said body member comprised of two mating sections, a hinge relatively pivoting said sections, whereby the tool may be opened or closed, a chamber formed in said body member by said mating surfaces, a U-shaped charge disposed in one of the mating surfaces and a die member in the other mating surface, means for detonating said charge whereby a connector with a conductor therein may be inserted in the tool and the sections closed to cause the die to partially crimp the connector to the conductor thus locking the conductor and connector in the tool and the explosive charge detonated to complete the crimped connection.

2. The device of claim 1 including means for disabling the detonating means when the tool is open.

3. A hand tool for crimping electrical connectors onto conductors including a plurality of mating sections forming a body member, a chamber formed in the body member by the mating surfaces and capable of receiving a connector and conductor therein, an explosive charge in said chamber and at least partially surrounding the connector, means for detonating said charge and releasable means for locking said sections together.

4. The device of claim 3 including means for disabling said detonating means when the sections are not locked together.

5. The device of claim 3 including die means in said chamber for partially deforming a connector when the sections are joined in mating relationship.

6. In a hand tool for crimping electrical connectors onto conductors, the combination comprising: a body member, a connector-receiving chamber in the body member, an opening in the chamber permitting the insertion of a conductor into the connector, means for containing an explosive charge within the chamber, said means being sustantially U-shaped and partially surrounding the periphery of the connector and following the contour thereof, means for detonating the explosive charge, and die means for partially deforming the connector prior to detonation of the explosive charge, whereby detonation of the charge deforms the connector onto the conductor.

7. The device of claim 6 wherein the body member comprises a plurality of sections movable between an open position and a closed position, and means in one of said sections for actuating said die means to partially crimp the connector.

8. A hand tool for crimping electrical connectors onto conductors comprising a body member, said body member comprised of a plurality of sections relatively pivoted together and having internal surfaces forming a connector-receiving portion, whereby the tool may be opened or closed to admit an electrical connector or conductor, a chamber in said body member also formed by the surfaces of said sections, a cartridge containing an explosive charge disposed in said chamber, a die member in one of said sections, and means for detonating said explosive charge to deform the connector by expansion of the cartridge.

9. A tool for crimping electrical connectors including a body member, an opening in the body member for receiving an electrical connector, an explosive cartridge in said body member so that a sidewall of the cartridge is disposed adjacent to the opening for receiving the connector, and means for exploding said cartridge to expand it to cause deformation of the connector.

References Cited in the file of this patent UNITED STATES PATENTS 

